Body mass index (BMI) is a method of screening for a weight category using the ratio of your height to your weight. The BMI is a measure of overweight that is corrected for height. Knowing your BMI is a way to tell if you are at a healthy weight. The higher your BMI, the greater your risk for weight-related health problems.
BMI below 18.5: Underweight
BMI 18.5 to 24.9: Healthy weight or "ideal body weight"
BMI 25 to 29.9: Overweight
BMI 30 and over: Obese
BMI 40 and over: Severe obesity
Find your BMI with an online BMI calculator tool, such as these from the CDC:
To figure out your BMI, find your height and weight (or the numbers closest to them) on the table below. Follow each column of numbers to where your height and weight meet on the table. That is your BMI.